1. Field of the Invention
The present invention relates to a vacuum eraser for blackboards and pertains to the removal of chalk dust from blackboards by combination an eraser and vacuum collecting devices. This vacuum eraser is convenience to be used as a result of the compact size design and the cordless vacuum ability.
2. Description of the Prior Art
The use of erasers in various designs and configurations is known in the prior art. These various eraser designs and configurations are utilized for the purpose of wiping off chalk dust from blackboards.
By way of example, the prior arts discloses are as follows:
U.S. Pat. No. 3,986,224 to Yang discloses an eraser with powder-collecting means (1976)
U.S. Pat. No. 4,007,509 to Odhner discloses blackboards eraser (1977)
U.S. Pat. No. 4,462,134 to Wang discloses blackboards eraser (1984)
U.S. Pat. No. 4,742,594 to Chen discloses blackboards eraser (1988)
U.S. Pat. No. 4,941,225 to Liao discloses automatic chalk-powder collecting device for blackboards eraser (1990)
U.S. Pat. No. 5,075,915 to Rodriguez discloses eraser cleaner (1991)
U.S. Pat. No. 5,099,541 to Tressler discloses blackboards eraser apparatus (1992).
U.S. Pat. No. 5,216,776 to Dennison discloses automatic blackboards eraser apparatus (1993)
U.S. Pat. No. 5,455,976 to Kim discloses apparatus for automatically brushing chalk powder off from blackboards eraser (1995)
U.S. Pat. No. D,366,670 to Huh discloses blackboards eraser (1996)
U.S. Pat. No. 5,530,984 to Walker discloses quick wipe eraser for chalkboards (1996)
After detail analysis the patented erasers in the prior art, they are all related to how to remove the chalk dust from blackboards completely and effectively. After using those erasers several times, the surface of eraser will be saturated with chalk dust and eventually the chalk dust will escape out and pollute to the air. The present invention for a Vacuum Eraser for Blackboards will vacuum out the chalk dust from the surface of eraser continuously so that is no pollution problem and will get better erasing every time by reason of the clean eraser surface.